Difference between Front End Engineering Design (FEED) and fabrication/construction?

[cxcxcx0505]

Can anyone explain the difference between Front End Engineering Design (FEED) and fabrication/construction in oil and gas sector? And also, what do Front End Engineering actually do? Thanks.

[feune111962]

The FEED takes place upstream the detailed engineering studies. It covers all the process engineering studies for a given project. Typical documents produced during the FEED are:
- PFD & Block diagram
- P&ID and line list
- Utilities & general facilities distribution and line list
- Equipment data sheet
- Control valves datasheet
- Cause an effect chart

I hope that this clear enough.

[mrkssastry]

FEED: Front End Engineering & Design

This the first stage of Engineering for any Project (Chemical / Petrochemical / Oil & Gas / Refinery etc) where the following discussed & decided.

1. Technical / Process Wise:
a. Material Balance (Mass & Heat)
b. Process Flow - How the various raw materials flow from start to end & in what form
c. Major equipments of the process - pumps, vessels, heat exchangers, filters, etc
d. Safety Systems requirement for process

Engineering Wise:

1. Approximate Load List - for motors, transformers, drives, High Voltage Switchgear, UPS size, Diesel Genertor requirements etc
2. Utilities required for the process - Air compressors, Nitrogen Plant, Fire Fighting systems, Hot Oil Heating Systems requirement, Air Dryers etc
3. Major Instrumentation Systems - PLC / SCADA / DCS system (which one or combination of the above etc)
4. Approximate Instrument List - Kind of Networks used, kind of Instruments used, system architecture (rough sketch / drawing showing the different networks connectivity between them)


Management Wise:

a. The total cost of the project - around X +20% approximation (within the accuracy of +/- 20% accuracy)
b. The total manpower requirement for the plant
c. Total List of Raw Materials requirement & their quantities
d. Approximate time required for completion of the project

Philosophies wise:

1. Plant Operating Philosophies / Plant Design Philosophy & design Basis
2. Instrumentation Engineering philosophy - Design & selection basis documentation
3. Control Systems Philosophies - Heirarchies being implemented, design basis for selection of PLC / SCADA / DCS Systems, Third Party Interfaces, OPC Interfaces, Serial Interfaces between systems, Interfaces between DCS, ESD, F&G systems
4. Safety Shutdown Systems philosophy - LOPA Studies / HAZOP studies / CHAZOP studies etc including SIL calculations.

Now apart from the above, the following are the deliverables at the end of the FEED.

1. Mass & Heat Balance Calculations
2. Process Flow Diagrams
3. Process & Instrumentation Diagrams (only 70 - 75% accurate)
4. Load list for electrical
5. Major Equipments & their Sizing (Major Equipments 100% accurate, however, there might be an addition of a one or two pumps / motors / blowers that might get added during the detail engineering stages but not vessels / heat exchangers or tanks).
6. Instrument list - which is 80% to 90% accurate.

However, please do remember the following:

1. Instrumentation Datasheets / Process Datasheets / Mechanical Datasheets are not the deliverables of FEED. They are preapred during the Detail Engineering Phase
2. Instruments Selection, Sizing Calculations are finalized / done during the detail engineering phase only.


Hope i am correct. However, request senior professionals to comment on the same.

Sastry Musti
Instrumentation & Control Systems Engineer

[Bever]

thank you for the usefull info

[daffodils]

I like how Sastry has broken the answer into different philosophies. I will try to answer in a more basic way
FEED - Done by Engineering Contractor (FEL-1 is business planning focused, FEL-2 - PFD focused, FEL-3 is P&ID focused). FEL-2/3 also involves significant work by all engineering disciplines (Mech, Inst, piping, electrical, CSA etc)

Fabrication - usually done by a vendor or fabrication company who is contracted by the engineering (FEED) contractor. Fabrication of vessels, columns, reactors based on specifications provided by the engineering contractor or maybe a technology licensor.

Construction: is done by a construction contractor. Can be same as engineering contractor (in cases like Bechtel etc) or a purely contruction company. The construction company works on the design of the engineering company to install / erect equipment made by fabricators.

[mrkssastry]

Daffodils,

Thanks for the reply & for a very short & sweet yet complete information regarding the FEL / FEED. Well done sir.

Sastry

[101043728]

Dear Sastry & Daffodils

Very informative. May I detail information for Mechanical Engineering discipline in FEL 2/3 please?

Many Regards,
Deven